1. Field of the Invention
The system of the present invention relates to multi-duct conduit systems. More particularly, the apparatus of the present invention relates to an assemblage for interconnecting ducts within a multi-duct conduit system particularly adapted for housing underground cable installations. The system would serve as a coupling arrangement to sealingly couple adjacent conduit sections end to end to form the continuing underground conduit system.
2. General Background
For certain transmission systems, wherein cables are laid underground, such as the light guide cables used in the transmission of telephone lines, in the normal installation of the system, the cables are housed through a light duct work, the ducts laid out in 20 to 30 foot sections, and in certain installations the ducts may appear in groups of three to four each duct housing a number of cables, and the ducts assembled as a group in order to house sufficient cable for the transmission.
Normally, the individual ducts housing the cable are then secured within an exterior main husings such as light-weight PVC pipe, so that the multi-duct housing are contained within a central housing for easier laying of the installation underground.
One of the recurring problems in this particular type of system is that the points at which the 20 to 30 foot lengths of interior housing must be coupled or joined so that the line may be continuously transmitted underground. This juncture, of course, must, in order to be suitable, be of such a nature that the ducts within the outer housing are coupled in such a way, of course, to provide a suitable connection between the ducts, and yet for the most part, be free of moisture and the exterior corrosive elements underground.
There are several products presently utilized in the marketplace, which attempt to provide for the proper coupling arrangement between ducts end to end, but fall short of their goal. One such coupling is the coupling manufactured by Dyka U.S.A., Inc., wherein the coupling includes an outer duct with the inner ducts positioned within the outer duct. There is included a coupling member wherein the inner ducts are fed into a support plate with each socket in the support plate accommodating a duct with a flexible gasket so that when the inner ducts are positioned in the coupling, the gaskets form a seal about the inner ducts during use. There is further provided a member to engage between the support plates to maintain the coupling in an overall coupled position.
In one embodiment there is further included an exterior collar member positioned around the juncture of the outer most casing to secure the outer most casing into sealing relationship. This arrangement falls short of providing a stable, secure joint, and often results in unsecure coupling of the segments of the housings.